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20-04-2022 | Rheumatology | News | Article

Bariatric surgery may reduce need for TKA in people with obesity, knee osteoarthritis

Author: Claire Barnard

medwireNews: Findings from a randomized controlled trial suggest that weight-loss surgery may negate the need for total knee arthroplasty (TKA) for some people with severe obesity and knee osteoarthritis (OA).

The trial was originally designed to test the impact of bariatric surgery on the risk for complications following TKA, but the study authors report the “striking finding” that almost a third (29.3%) of the 41 participants randomly assigned to receive bariatric surgery subsequently declined their planned TKA due to symptom improvement, compared with just 4.9% of the 41 individuals who instead received usual weight management advice.

“Although not the primary intent of our study, these results indicate that for a substantial portion of patients with severe obesity and knee OA, symptoms may be effectively managed with weight-loss strategies alone,” write the study authors in JAMA Network Open.

Peter Choong (St Vincent’s Hospital Melbourne, Victoria, Australia) and co-investigators say that the reduction in the proportion of patients undergoing TKA resulted in early termination of the trial “because it was apparent that the study would not be completed within an acceptable period.”

The study included 82 people aged 65 years or younger with a BMI of at least 35 kg/m2 who were on a surgical waiting list for primary TKA. In the intervention group, the median time from enrollment to bariatric surgery was 64 days, and the median time from enrollment to TKA was 522 days.

“We chose bariatric surgery as the weight loss intervention because it can reliably induce and sustain 15% to 30% total body weight loss beyond 10 years,” explain the researchers. They note that laparoscopic adjustable gastric banding was chosen as the bariatric surgery type as it was the most commonly performed procedure in their location at the time of the study.

For the primary analysis, which included all 82 participants irrespective of whether or not they eventually underwent TKA, those assigned to bariatric surgery had a significant 71% lower risk for the primary composite outcome of TKA complications than those in the usual care group, at rates of 14.6% versus 36.6%. However, only 29 people in the bariatric surgery group underwent TKA, compared with 39 people in the control group. TKA complications were defined as all-cause mortality, perioperative or postoperative complications resulting in delayed hospital discharge, wound complications, unplanned procedures, or readmission during a median follow-up of 24 months in the bariatric surgery group and 27 months in the control group.

Choong et al say that people in the bariatric surgery arm achieved “substantial and clinically significant” weight loss, from an average of 116.1 kg at baseline to 96.6 kg at month 12, whereas those in the usual care arm experienced a much smaller loss from 114.0 to 111.5 kg, giving a significant between-group difference of 16.5 kg.

medwireNews is an independent medical news service provided by Springer Healthcare Ltd. © 2022 Springer Healthcare Ltd, part of the Springer Nature Group

JAMA Netw Open 2022; 5: e226722

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